In general, buildings have various windows and doors installed in openings to separate the interior from the exterior.
On the one hand, the most common form of windows and doors installed in the wall of a building is to install a window frame in the structure and to install a glass window in the frame to separate the interior from the exterior. Commonly, the glass window is either fixed in the frame or positioned in the frame so that it moves to open and close.
To control the amount of sunlight that comes through windows, curtains, blinds, or roll screens are often installed, but this requires extra space and cost.
Still further, images of a particular product or company can be attached on the window for advertising purposes, but there are disadvantages such as the difficulty of changing the images and the loss of a clear view due to the attached images.
In the consideration of these issues, I previously invented a multipurpose advertisement board using a window, now U.S. Pat. No. 8,069,597 B2. This previous multipurpose advertisement board included winding rollers at the upper end and the lower end of the frame, and a film having multiple images. Such a multipurpose advertisement board has an advantage that it can display multiple images by simply rolling one of the rollers to wind the film, without a complicated preparation. However, such multipurpose advertisement board has a restricted advertising effect as it can only display a number of images in order. It cannot change the color of the image to adapt to the weather or the surroundings, or put dynamics to the image.